No Polling Job for some of my switches

Hi All,
I'm seeing some weirdness with the polling - several of my switches just arn't discovering MAC addresses at all.  When I check the UDT Status I can't see any polling jobs (neither Polling or Layer3).  I couldn't seem to find any way to remove and re-add the device to see if it created the polling job - I tried unmanage/remanage on the device and also tried unmonitoring the ports and remonitoring - no luck.
The switches concerned are all Cisco 6509E with sup32 running IOS or 6513 running CatOS/IOS hybrid.  I do have other switches which are basically identical which are working correctly (and are running the same os versions/hw).
Any ideas on how I can get this fixed?  I dont want to delete the device entirely since that remvoes the NPM object and I'd lose all my data on them.

Also - does anyone know how the "hostname" field gets populated?  When I look at port history I only ever have MAC and IP listed (although a search will find the hostname).
Thanks, Sean